Updated: Automated "git bisect" will make your day

Added methods to keep the line number steady while you time-travel between commits:

Copy the file to a new location that is not tracked by Git
Run RSpec example by description
Run RSpec example by nesting index

Changes

...
So you're hunting down a regression (or just a bug) and want to use [`git bisect`](https://makandracards.com/makandra/943-how-to-use-git-bisect-to-find-bugs-and-regressions) to find out when it was introduced? Smart kid. 
If you have a shell command ready to reveal if your current state is good or bad, you can have git do most of the work for you.
Using `git bisect run <your command>` you can tell git that your command will reveal the issue; git on the other hand will use the return value of that call to decide if the state is good or bad.
1. First, start bisecting
        git bisect start
2. Then tell git which revisions are good and which are bad. You need to manually run your command for this, or just know which ones work and don't work.
       git bisect bad
       git bisect good abcdef1234
3. Now tell git what to do
       git bisect run bundle exec cucumber features/my.feature:42
4. Wait for the results to come in: Git will bisect until it knows which commit was the first bad one.
5. Finish bisect
       git bisect reset
For more information, see [the original "git bisect" card](https://makandracards.com/makandra/943-how-to-use-git-bisect-to-find-bugs-and-regressions).
-> [important]
-> Mind that **your command needs to work across all revisions that you will be bisecting**. If you're referencing a test file that's under version control, make sure you always run the correct test; copying the file to a location outside of your repository might be a viable solution to keep the line number steady while you time-travel between commits.
+## The command must work across revisions
+
+Mind that **your command needs to work across all revisions that you will be bisecting**. If you're referencing a test file that's under version control, make sure you always run the correct test.There are several options to keep the **line number** steady while you time-travel between commits:
+
+- Copy the file to a new location that is not tracked by Git
+- [Run RSpec example by description](https://makandracards.com/makandra/47400-rspec-running-examples-name-running-single-shared-example)
+- [Run RSpec example by nesting index](https://makandracards.com/makandra/624970-rspec-executing-specs-example-nesting-index)

Henning Koch

makandra.de

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License

Source code in this card is licensed under the MIT License.

Posted by Henning Koch to makandra dev (2025-03-24 08:13)